1. Field of the Invention
The present invention relates to ozone generators for pools and spas, and more particularly to a feedback arrangement responsive to the impedance changes of a resonant tank circuit for producing a coronal plasma field that generates ozone associated with the inadvertent presence of water within the gap between the coronal plates.
2. Description of the Prior Art
The use of the chemically reactive nature of ozone as a sanitizing mechanism for controlling unwanted microbial growth has been known in the past, with particular recent focus in the application thereof for sterilizing the water in a pool or a spa. Simply, as the cost and the cumulative environmental impact of chlorination increases the search for viable alternatives has commensurately also increased, with the current focus now particularly directed to ozone as a sterilization mechanism replacing or augmenting the use of chlorine and the generation thereof has matured.
While the highly reactive nature of ozone is now widely appreciated also are its inherent risks and, as a consequence, various ozone generator configurations have been proposed in the past that in one manner or another control and/or limit its local production rate, as exemplified by the teachings of U.S. Pat. No. 5,443,800 to Dunder and U.S. Pat. No. 5,540,898 to Davidson; that alter the oscillation rate of the driving circuit to a fixed ratio of its tank circuit resonance as in U.S. Pat. No. 5,770,168 to Carlsten et al.; and/or respond to the tank circuit impedance as in U.S. Pat. No. 5,474,750 to Racca et al. While suitable for the purposes intended each of the foregoing either shuts off all ozone generation (e.g., Racca et al.) or is limited in its control authority range to the normal fluctuations in the ambient background and therefore do not respond with any significant effect in those circumstances where the ozone generating electrodes are deployed above a water surface and on occasion are fully immersed. This immersed state is particularly probable in a highly used and agitated pool or spa when the sterilization benefits of ozone are desired, resulting in compromised sterilization right when the use is heavy and enhanced.
The efficacy of some ozone generation even once fully immersed has been known in the past, particularly where the electrode separation gaps are small, as exemplified in the teachings of U.S. Pat. No. 5,154,895 to Mooa, and others. Thus by proper design of the electrode geometry (and/or the materials thereof) the continued operation of the sterilization process can be carried on even in the most vigorous water conditions. In light of this expanded operating range of water content that can be accommodated within the electrode gap a commensurate expansion in the authority of any regulating feedback is extensively desired and it is one such am arrangement that is disclosed herein.